Numerous investigations have shown that activation of biosynthesis and accumulation of polyamines in tissue accompany both normal and neoplastic cell growth. The biosynthesis of polyamines in tissue is finely controlled and it seems that at least part of this control is feedback inhibition by increased levels of spermidine and spermine in cell. We propose that in tumor tissue the regulatory effect of spermidine and spermine on the enzymes involved is impaired, probably as a result of increased rates of biotransformation of these amines to rapidly excreted conjugates. Consistent with the proposal is the recent observation that patients with diagnosed cancer excrete elevated levels of polyamines conjugates in urine. In these studies we intend to isolate, purify and elucidate the structure of these conjugates. Furthermore, it has been suggested that urinary polyamine levels could serve as a tool for the detection and monitoring of cancer in patients. Unfortunately, the available methods for the determination of polyamines are not suitable for routine examination of large number of urine samples. In these studies we intend to develop analytical methods which would permit the reliable and convenient determination of polyamines in urine and other biological samples.